Dual cutoff blower



Oct. 12, 1965 Filed Dec. 5, 1963 DUAL CUTOFF BLOWER 2 Sheets-Sheet 2 rT- E United States Patent Office 3,211,360 DUAL CUTOFF BLOWER Roger T. Lyman, Princeton, and William G. Stewart, Trenton, N.J., assignors to Kooltronic Fan Company, Princeton, N..l., a corporation of New Jersey Filed Dec. 5, 1963, Ser. No. 328,239 Claims. (Cl. 230-47) This invention relates to blowers, and more specifically relates to a novel arrangement for blowers which have more than a single outlet port.

More specifically, the invention provides a novel scroll configuration which permits extremely efficient blower operation for a multiple port blower. The novel arrange ment of the invention is applicable to those systems where there are a multiple number of ports which may or may not have similar outlet flow requirements. The invention further contemplates a novel manner for securing the scroll outline to a base to substantially simplify manufacturing techniques, and moreover provides a novel arrangement of filters for improved filter operation of the blower.

Accordingly, a primary object of this invention is to provide a novel, extremely efficient, multiple port blower.

A further object of this invention is to provide a novel and inexpensive method of manufacture for the securement of complexly shaped scrolls of a blower to the support housing of the blower.

Yet a further object of this invention is to provide a novel filter arrangement for packaged blowers.

These and other objects of this invention will become apparent from the following description when taken in connection with the drawings, in which:

FIGURE 1 schematically illustrates the scroll development for a three portblower housing designed in accordance with the present invention.

FIGURE 2 is a top view of a two port blower with the cover removed wherein the complexly shaped scroll is secured to the housing in accordance with the present invention.

FIGURE 3 is a cross-sectional view of FIGURE 2 taken across the lines 33 in FIGURE 2.

FIGURE 4 is a side view of one of the ports of FIG- URE 2.

FIGURE 5 illustrates a detail view of the manner in which the scroll housing of FIGURES 2, 3 and 4 can be secured to the base. 7

FIGURE 6 shows an alternate method of securement to that of FIGURE 5.

Blowers of the type to which the invention relates are commonly used as packaged cooling apparatus for installation in electronic component cabinets, relay racks, and the like.

The common practice in such units has been to provide a blower having a single discharge port. The design of such single discharge devices is quite well known to the art. There are, however, many applications where multiple ports are necessary where air flow is required for more than one location on the packaged cooling device.

While there are many types of multiple type outlet blowers known to the art, these devices have always failed to operate with the same efficiency as have the wellknown single outlet devices.

37,211,360 Patented Oct. 12, 1965 The present invention relates to a novel arrangement for multiple port units which operate with an efiiciency which is comparable to that of the common single outlet device.

More specifically, and with reference to FIGURE 1, it has been found that when the scroll contour, cutofi radii and discharge radii are held to specific dimensions, air discharge may be obtained with the efliciency previously achieved only with single blower designs.

FIGURE 1 illustrates the scroll arrangement of a three port blower which has outlet ports 10, 11 and 12. For purposes of illustration, the ports 10 and 11 will each have to supply 25% of the total flow available from the blower, while port 12 is intended to supply 50% of the total flow. It has been found that where the blower housing has been caused to conform to a novel configuration wherein port location and size is based on the portion of total air flow desired from each port and where the cutolf radii R R and R are caused to conform to a novel size, and at the same time the outlet ports terminating in discharge radii P P and P are formed to a novel dimension, the desired high etliciency operation results. Thus, if the base circle diameter is called D and the diameter D is the diameter of the blower wheel, the base circle is made to have a diameter C is a clearance constant, and could, for example, be 1.225 to provide a reasonable blower noise level, while It is the number of outlet ports. The clearance constant C is increased in order to reduce the blower noise level.

Thereafter, the spiral shapes desired of the scroll sec tion 13, 14 and 15 are computed in the usual manner from the base circle D with a diffuser angle of preferably 10 being selected. That is to say, the spiral .path always forms an angle of 10 with respect to the base circle. Thereafter, and in accordance with the invention, the radii R R and R are computed from the novel relation C D times the percentage flow required from the particular port. The value C is a cutoff radius constant and it has been found that for best performance C should be of the order of 0.08. The cutotfs so defined are generated tangent to D at the point of origin of each following scroll segment. The discharge radii P P and P are then mounted in accordance with the invention, computed from a relationship C D times the percentage discharge of the port plus one-half of the cutoff radius R of that port. The value C is a discharge radius constant, and for best performance has been found to be of the order of 0.7.

The discharge radius P is that value as shown in FIG- URE 1 which is the distance from the center of the cutolf radii of the first scroll section to a tangent to the end of the adjacent scroll section shown as the line T in FIG- URE 1, which forms the port. It is to be noted that the novel structures which are developed from the relation ships given above can be used for the design of any general multiple port blower housing, wherein the various ports are arranged to provide any percentage of the total flow as would be desired.

Thus, in FIGURES 2, 3 and 4, we have illustrated a specific embodiment of the invention for a two port blower housing wherein the discharge from each of the ports is equal. It will be seen that the scrolls will have complex shapes which must be accurately reproduced mechanically to obtain the best blower performance. This has frequently been a source of great manufacturing difficulty, even in the case of single port blowers since it is difiicult to mechanically cause the scrolls to follow the desired mathematical shape.

A further aspect of the present invention lies in a novel manner for forcing the scroll outline to follow its predetermined shape. This is best shown in FIGURES 2, 3 and 4 where the figures illustrate a housing which has a front grille 21 (FIGURE 3) through which air flow may enter, as illustrated by the arrows, and a cover 22 which is shown removed in FIGURE 2. The main housing 20 then has a bottom section 23 (FIGURES 2 and 3) to which the two scrolls 24 and 25 are to be secured. The two scrolls 24 and 25 then receive a scroll cover 26 which may be a preformed shaped metal stamping having the edge regions 27 and 28 formed integrally therewith or formed of separate structural elements. The outer section 27 is then welded, for example, to the upper portions of scrolls 24 and 25.

One of the most difficult tasks in forming this type of housing is in being sure that the scroll sections 24 and 25 follow precisely the precalculated curve which they must take to define their port openings 30 and 31.

In accordance with the present invention, we have provided a plurality of novel angle elements such as angles 40, 41, 42 and 43 which extend completely about the lower edge of scrolls 24 and 25. More specifically, and prior to the securement of scrolls 24 and 25 to base 23, the desired pattern which the scrolls are to take is traced on the bottom.

Thereafter, and as shown in FIGURE 5, the angle such as angle is placed directly on the scribed line on bottom 23 and is welded in place as by the weld 44.

Therefore, the' various angle members will define the mathematical pattern which is to be followed, whereby the scroll, which is of sheet metal, can merely be bent to form over the welded angles and thereafter may be welded to the angles as at weld 45 in FIGURE 5. The scrolls could be otherwise secured to the angles as by the use of self-tapping screws, shown in FIGURE 6 for self tapping screw 46.

After the precise placement of the scroll sections 24 and 25 in the above described manner, the scroll top section 26 is welded in position.

Thereafter, a pair of support rods and 51 may be secured directly to the upper scroll surface 26 as by welding or through a screw connection, wherein the rods 50 and 51 carry the motor 52. The motor 52 has an extending hub 53 to which a blower wheel 54 having suitable blades such as blades 55 and 56 are connected. The blades of wheel 54 are best shown in FIGURE 4.

During operation, it will be apparent that the wheel 54 will be rotated by motor 52 whereby air coming through grille 21 will be discharged from ports 30 and 31 in a highly efiicient manner, particularly where the novel scroll design described in FIGURE 1 is followed.

As a further feature of the invention, a novel arrangement of filters is provided wherein two filters 60 and 61 which are coextensive with grille 21 intercept the air coming through grille 21 before it enters the wheel 54. The filters 60 and 61 which may be of any desired type may be fitted into appropriate slots or runners in the opposing sidewalls of the housing and are so positioned that the air coming in through the bottom of grille 21 passes through filter 61, while the air coming into the top of the grille 21 goes through the filter 60.

This novel arrangement permits an extremely large filter area so that the rate of flow of air through the filters is decreased for a given air volume. Accordingly, the

filter action proceeds in a much more etficient manner than had the filter area been substantially equal to the area of grille 21, as in the prior art.

Although this invention has been described with respect to preferred embodiments thereof, it should be understood that many variations and modifications will now be obvious to those skilled in the art, and it is preferred therefore that the scope of the invention be limited not by the specific disclosure herein but only by the appended claims.

The embodiments of the invention in which an exclusive privilege or property is claimed are defined as follows:

1. A multiple port blower comprising a plurality of scrolls and a blower wheel; each of said scrolls forming an enclosure about said wheel and forming a plurality of ports at the adjacent ends of said scrolls; one end of said scrolls each having an outwardly bent section, the other end of each of said scrolls being straight; each of said ports being defined by adjacent outwardly bent sections and straight sections respectively of adjacent scrolls; each of said outwardly bent scrolls being bent on a radius R determined by the relation R=C D F where C is approximately 0.08, D is the diameter of said wheel and F is the percentage flow out of the said port corresponding to said outwardly bent scroll; each of said ports having a discharge radius P determined by the relation P=C D +V2R where C is approximately 0.7.

2. The device substantially as set forth in claim 1 wherein each of said scrolls has a diffuser angle of the order of 10.

3. A blower comprising a motor, a blower wheel driven by said motor, a scroll of sheet metal having a predetermined shape and receiving said wheel therein, and a housing having wall members, a bottom member and an outlet port in one of said wall members in communication with said scroll; securing means for securing said scroll being secured along one edge thereof to said bottom; a grille member for one of said wall members and a first and second air filter; said first filter extending across a first portion of said grille; said second filter extending from the end of said first filter and extending angularly away from said grille; said first and second filters receiving all of the air passing through said grille.

4. A multiple port blower comprising a plurality of scrolls and a blower wheel; said scrolls forming an enclosure about said wheel and forming a plurality of ports at the adjacent ends of said scrolls; one end of said scrolls each having an outwardly bent section, the other end of each of said scrolls being straight; each of said ports being defined by adjacent outwardly bent sections and straight sections respectively of adjacent scrolls; each of said outwardly bent sections being bent on a radius R determined by the relation R=C D F where C is approximately 0.08, D is the diameter of said wheel and F is the percentage fiow out of the said port corresponding to said outwardly bent scroll; each of said ports having a discharge radius P determined by the relation where C is approximately 0.7; each of said scrolls having a diffuser angle of the order of 10; and a housing; said housing having a bottom member and wall members secured thereto; said wall members having openings therein in registry with said ports; a securing means for securing said plurality of scrolls to said bottom of said housing; said securing means including angle shaped members having one leg welded to said bottom to define the predetermined shape required of said scrolls, and a second leg of each of said angles being secured to said scrolls.

5. A blower comprising a motor, a blower wheel driven by said motor, a scroll of sheet metal having a predetermined shape and receiving said wheel therein and a housing having wall members, a bottom member and an outlet port in one of said wall members in communication with said scroll; securing means for securing said scroll being secured along one edge thereof to said bottom; said securing means comprising a plurality of angle members having the bases thereof welded to said bottom of said housing along a curve given by the theoretical required shape of said scroll; said scroll being secured to the upwardly extending section of said angles; a grille member for one of said wall members and a first and second air filter; said first filter extending across a first portion of said grille, said second filter extending from the end of said first filter and extending angularly away from said grille; said first and second filters receiving all of the air passing through said grille.

References Cited by the Examiner UNITED STATES PATENTS 2,148,254 2/39 Bergstrom 23047 2,171,248 8/39 Berkel 230-127 2,330,938 10/43 Williams 230-47 2,482,519 9/49 Schwarz 230-117 3,147,909 9/ 64 Novitsky 23047 FOREIGN PATENTS 947,190 8/56 Germany. 583,729 12/46 Great Britain.

DONLEY J. STOCKING, Primary Examiner.

HENRY F. RADUAZO, Examiner. 

1. A MULTIPLE PORT BLOWER COMPRISING A PLURALITY OF SCROLLS AND A BLOWER WHEEL; EACH OF SAID SCROLLS FORMING AN ENCLOSURE ABOUT SAID WHEEL AND FORMING A PLURALITY OF PORTS AT THE ADJACENT ENDS OF SAID SCROLLS; ONE END OF SAID SCROLLS EACH HAVING AN OUTWARDLY BENT SECTIN, THE OTHER END OF EACH OF SAID SCROLLS BEING STRAIGHT; EACH OF SAID PORTS BEING DEFINED BY ADJACENT OUTWARDLY BENT SECTONS AND STRAIGHT SECTIONS RESPECTIVELY OF ADJACENT SCROLLS; EACH OF SAID OUTWARDLY BENT SCROLLS BEING BENT ON A RADIUS R DETERMINED BY THE RELATION R=C1DWF WHERE C1 IS APPROXIMATELY 0.08 DW IS THE DIAMETER OF SAID WHEEL AND F IS THE PERCENTAGE FLOW OUT OF THE SAID PORT CORRESPONDING TO SAID OUTWARDLY BENT SCROLL; EACH OF SAID PORTS HAVING A DISCHARGE RADIUS P DETERMINED BY THE RELATION P=C2DW+1/2R WHERE C2 IS APPROXIMATELY 0.7. 